Answer:
Step-by-step explanation:
[tex]1+cot^2x = csc^2x= \frac{1}{sin^2x}[/tex]
it becomes
[tex]\frac{1}{sin^2x}*\frac{sin^2x}{cos^2x}=\frac{1}{cos^2x}=sec^2x[/tex]
Done
